No abstract

Research in plant pathology has increasingly focused on developing environmentally friendly, effective strategies for controlling plant diseases. Cyanobacteria, including Desmonostoc muscorum, Anabaena oryzae, and Arthrospiraplatensis, were applied to Capsicum annuum L. to induce immunity against Fusarium wilt. Soil irrigation and foliar shoots (FS) application were used in this investigation. The disease symptoms, disease index, osmotic contents, total phenol, Malondialdehyde (MDA), hydrogen peroxide (H2O2), antioxidant enzymes (activity and isozymes), endogenous hormone content, and response to stimulation of defense resistance in infected plants were assessed. Results demonstrated that using all cyanobacterial aqueous extracts significantly reduced the risk of infection with Fusarium oxysporum. One of the most effective ways to combat the disease was through foliar spraying with Arthrospira platensis, Desmonostoc muscorum, and Anabaena oryzae (which provided 95, 90, and 69% protection percent, respectively). All metabolic resistance indices increased significantly following the application of the cyanobacterial aqueous extracts. Growth, metabolic characteristics, and phenols increased due to the application of cyanobacteria. Polyphenol oxidase (PPO) and peroxidase (POD) expressions improved in response to cyanobacteria application. Furthermore, treatment by cyanobacteria enhanced salicylic acid (SA) and Indole-3-Acetic Acid (IAA) in the infected plants while decreasing Abscisic acid (ABA). The infected pepper plant recovered from Fusarium wilt because cyanobacterial extract contained many biologically active compounds. The application of cyanobacteria through foliar spraying seems to be an effective approach to relieve the toxic influences of F. oxysporum on infected pepper plants as green and alternative therapeutic nutrients of chemical fungicides.

No abstract

The growth response and biological activity of the cyanobacterium Oscillatoria sancta were investigated in starvation conditions. Oscillatoria sancta growth potential was examined on BG11 and Zarrouk’s media. Zarrouk’s medium supported the maximum growth of the test cyanobacterium. Zarrouk’s medium composition was modified by excluding CaCl2·2H2O, NaCl, EDTA (Na), micronutrients, and replacing sodium nitrate with urea. Using Zarrouk’s medium and three different concentrations of modified Zarrouk’s media (Treatments 1–3), the growth response of Oscillatoria sancta (MZ366482) was examined and compared. Zarrouk’s medium and modified Zarrouk’s medium at 12.5% nutrient concentration had non-significant differences in both the dry weight biomass and total protein of Oscillatoria sancta. Oscillatoria sancta crude biomass extracts grown on Zarrouk’s and modified Zarrouk’s media (T3) inhibited human breast cancer, pathogenic bacteria, and acetylcholinesterase activity. Oscillatoria sancta grown on T3 showed the most potency against MDA-MB-231 cells with an IC50 of 165.2 µg mL−1, antibacterial activity only against Bacillus cereus (17.2 mm) and Staphylococcus aureus (15.3 mm), and acetylcholinesterase inhibition activity by 60.7%. Thus, it is advisable to use the 12.5% nutrient concentration of modified Zarrouk’s medium as a reduced-cost medium for mass cultivation of Oscillatoria sancta with potential anticancer, antibacterial diseases, and anti-Alzheimer purposes.

Cyanobacteria comprise a good natural resource of a potential variety of neuro-chemicals, including acetylcholinesterase inhibitors essential for Alzheimer’s disease treatment. Accordingly, eight different cyanobacterial species were isolated, identified, and evaluated on their growth on different standard nutrient media. It was found that the modified Navicula medium supported the highest growth of the test cyanobacteria. The effects of methylene chloride/methanol crude extracts of the test cyanobacteria on acetylcholinesterase activity were examined and compared. Anabaena variabilis (KU696637.1) crude extract recorded the highest acetylcholinesterase inhibition (62 ± 1.3%). Navicula medium chemical components were optimized through a Plackett–Burman factorial design. The biomass of Anabaena variabilis increased significantly when grown on the optimized medium compared to that of control. The chemical analysis of the fractions derived from Anabaena variabilis showed the presence of two compounds in significant amounts: the flavonoid 5,7-dihydroxy-2-phenyl-4H-chrome-4-one and the alkaloid 4-phenyl-2-(pyridin-3-yl) quinazoline. Molecular docking studies revealed that both compounds interact with the allosteric binding site of acetylcholinesterase at the periphery with π-π stackings with Tyr341 and Trp286 with good, predicted partition coefficient. The compounds obtained from this study open the door for promising drug candidates to treat Alzheimer’s disease for their better pharmacodynamics and pharmacokinetic properties.